CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2018	May 31, 2017
Income Statement [Abstract]
Net sales	$ 1,204,484	$ 1,044,713	$ 3,335,285	$ 2,759,939
Costs and expenses:
Cost of goods sold	1,035,914	896,277	2,896,531	2,357,867
Selling, general and administrative expenses	101,422	93,415	306,009	282,384
Interest expense	11,511	12,448	25,303	38,212
Total costs and expenses	1,148,847	1,002,140	3,227,843	2,678,463
Earnings from continuing operations before income taxes	55,637	42,573	107,442	81,476
Income taxes	13,312	11,006	23,465	21,231
Earnings from continuing operations	42,325	31,567	83,977	60,245
Earnings (loss) from discontinued operations before income taxes (benefit)	(3,389)	9,325	5,021	19,687
Income taxes (benefit)	(1,029)	1,626	2,052	4,059
Earnings (loss) from discontinued operations	(2,360)	7,699	2,969	15,628
Net earnings	$ 39,965	$ 39,266	$ 86,946	$ 75,873
Basic earnings (loss) per share
Earnings from continuing operations (in USD per share)	$ 0.36	$ 0.27	$ 0.72	$ 0.52
Earnings (loss) from discontinued operations (in USD per share)	(0.02)	0.07	0.03	0.14
Net earnings (in USD per share)	0.34	0.34	0.74	0.66
Diluted earnings (loss) per share
Earnings from continuing operations (in USD per share)	0.36	0.27	0.71	0.51
Earnings (loss) from discontinued operations (in USD per share)	(0.02)	0.07	0.03	0.13
Net earnings (in USD per share)	0.34	0.34	0.74	0.65
Cash dividends per share (in USD per share)	$ 0.12	$ 0.12	$ 0.36	$ 0.36
Average basic shares outstanding	117,111,799	115,886,372	116,722,504	115,574,289
Average diluted shares outstanding	118,254,791	117,205,369	118,050,864	117,087,341